NASA's Asteroid Redirect Mission aims to capture an asteroid in a high-tech "bag" and tow it closer to Earth for extensive studies and research. The plan is to use a robotic spacecraft to hunt and obtain an asteroid similar to those that threaten Earth. As of 2015, the plan was still in active development, with NASA estimating that the mission may be able to take place sometime during the 2020s.
NASA has been working on its Asteroid Redirect Mission since the early 2010s, and the agency has identified candidate asteroids that could be captured and towed toward Earth with a masive container known as an asteroid capture bag. This bag would be large enough to hold an asteroid approximately 25 feet in diameter. The robotic spacecraft would then tow the asteroid into a wide orbit around the moon, which would ensure that it could be studied without being a direct threat to Earth.